Device for determining the condition of alpha gas



2' M. c. w. TOMLINSON 1,883,116

. DEVICE FOR DETERMINING THE CONDITION OF A GAS Filed Feb. 16. 1929 I'll l l'l I I I I Patented Oct. 18, 1932 UNITED STATES PATENT OFFICEMALCOLM CLAIRE WEYANT TOMLINSON, OF LOCH ARBOUR, NEW JERSEY, ASSIGNOR TOWESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., ACORPORATION OF NEW YORK DEVICE FOR DETERMINING THE CONDITION OF A GASApplication filed February 16, 1929. Serial No. 340,640.

This invention relates to a device for determining the condition of agas, and more particularly the dew point thereof.

The primary object of the invention is to provide a simple and efficientdevice for accurately determining a characteristic of a gas.

In order to attain this and other objects and in accordance with thegeneral features of the invention, one embodiment thereof includes achamber having openings for a source oflight and for the inlet andoutlet of a gas. the dew point of which is to be determined. Upon theadmission of the gas into the chamber, the gas comes in contact with aplatinum plate coated with platinum black which is subjected exteriorlyof the chamber to a refrigerant until the dew point of the gas isreached; that is, until droplets of moisture or frost flakes appear onthe platinum black. The beams of light from the source thereof, directedon the platinum black, are then reflected by the droplets of moisture orfrost flakes to the polished interior of the chamber, and thence to alight sensitive cell for controlling an indicator or recorder. Thetemperature at which condensation takes place is indicated by athermocouple attached to the platinum plate within the chamber and asuitable associated instrument.

In an alternative embodiment of the invention, the light sensitivecellis omitted and the black surface of the platinum plate is observedthrough a microscope.

It is believed that a complete understanding of the invention may be hadby reference to, the following description taken in conjunction with theaccompanying drawing, in which Fig. 1 is a fragmentary cross sectionalview of a device embodying the features of the invention shown inassociation with a diagrammatic view of an indicating mechanism and Fig.2 is a fragmentary cross sectional view of an apparatus embodying amodified form of the invention.

Referring now to Fig. 1 of the drawing, a container composed of amaterial having poor heat conducting qualities, such as balsa wood, isprovided with a circular opening 11 in which a metallic chamber'12 isseated to form an air-tight connection with the container. The chamber12 is of spherical shape and is divided into two halves, 13 and 14; thelower half 13 having an opening 15, the walls of which are suitablysealed to a box 20. In the top of the box is an insert of sheet platinum21, the upper surface of which, within the chamber 12, is covered withplatinum black. In place of the thin sheet of platinum, a sheet of lead,bismuth, rosemetal or any other metal of low heat conductivity having asurface covered with platinum black may .be successfully used. Inlet andoutlet valves 2223, respectively, for the box 20 are provided foradmitting a refrigerant, such as carbon dioxide, sulphur dioxide, ethylchloride, methyl chloride, or butane, upon the range of the temperaturesdesired. A thermocouple2-l placed on the platinum sheet 21 is connectedto a suitable instrument 45, well known to the art, for indicating thetemperature. The upper half 14 of the chamher 12 is sealed to the lowerhalf 13 and-has inlet and outlet valves 27 and 2S,'respectively, forcontrolling the admission into the chamber of a gas to be tested. At thetop of the chamber 21 is a tube 30 having therein an aspheric condenserlens 31 for directing a beam of light from a lamp 32 on the platinumsheet 21. Also mounted in this tube are a pair of spaced glass filters33-33 for removing the glare from the light beam and for cooling thebeam of light as it passes through the intervening air space.

To the right of the tube 30, within the chamber 12, a light-proofcurtain 36 is positioned so as to shield a photoelectric cell 37 fromany direct light coming from the lamp 32. The photoelectric cell 37 isconnected to the input circuit of a two-stage vacuum tube amplifier 38through a battery 39 and a high resistance 40. Connected to the outputside of the amplifier 38 is a relay 41 adapted to operate a signalcircuit having a battery 42 and an incandescent lamp 43. It will beunderstood that any suitable indicator or recorder can be connected tothe output side of the amplifier 38.

In operating the device to determine the dew point of the gas, the inletvalve 27 and depending outlet valve 28 are adjusted to-permit acontinuous flow of the gas to be tested into the chamber 12. The inletvalve 22 of the box is then opened to admit small quantities of 'lcarbon dioxide from a source of supply thereof (not shown). As the gasto be tested comes into contact with the sheet of platinum and thetemperature thereof decreases due to the action of the refrigerant, suchas carbon di- 10 oxide, droplets of moisture or frost flakes will appearon the thelatinumsheet 21 when'thcdew point is reac ed. The beam oflight from the lamp: 32 directed on the platinum black is reflectc B bythe droplets of moisture or' frost flakes to the polished interior ofthe chamber 12 and thence to the photoelectric cell 37. The light beamthus enters andenergizes the photoelectric cell and causes a current toflow from M the battery 39 through the resistance 40,

thereby changing the potential of the input circuit. This change causesthe amplifier 38 to transmit sufiicient current to operate the relay 41which closes a circuit, and causing the battery 42 to light the lamp 43.The illumination of this lamp is a signal to the operator that the dewpoint of the gas has been reached. By means of the thermocouple 24, theobserver notes the temperature at which the condensation took place andthis is the dew point tem erature.

Thus it is seen that v y the use of the simple device of this invention,accurate determinations can be made of the dew points of not onlyair-water vapor samples, but also of any other air-vapor mixtures.

In a modified form of the invention as illustrated by Fig. 2, the dewpoint determinator includes two balsa wood containers -51 havingwaterproofed internal walls. The lower container 51 has a cold gas.space 52, at the bottom-of which is positioned a Dewar flask 53containing liquid air for a refrigerant. Connected with the cold gas 4space 52 are valves 54,.55 for admittin air to thereby prevent thebuilding up 0 gas pressures 11 means black. This chamber is alsoprovided with inlet and outlet valves 62-'63 for controlling theadmission of a gas to be tested, and with a microscope 64 for observingthe presence of droplets of moisture or frost flakes on the platinumblack covering the sheet of platinum 61. A tube 67 extending into the camber 60 directs light from a lamp 68 to effectively illuminate thesheet of platinum 61. In order to determine accurately the temperaturewithin the chamber 60,-.a thermocouple 72 is provided.

In operation, the gas platinum black covering,

. of light, means for means for introducing t within the space 52 and tofurnish. for controlling the temperature. Within the upper balsa woodcontainer 50 is positioned a metallic chamber 60 having a' platinumsheet 61 covered with platinum" light into saidlight sensitive means,

to be tested is introduced into the chamber 60 through the valves 62-453and comes into contact with the platinum sheet 61 which is exposed tothe refrigerating action of the liquid flask 53. When the dew point ofthe gas is reached, droplets. of moisture or frost akes are formed andtheir presence can be readily ascertained lg observing the platinumsheet 61 through e microscope 64. Upon their appearance, the dew pointtemperature reading is obtained by the use of the thermocouple 7 2 and asuitable associated instrument 75.

It will be understood that the embodiments of the invention hereindescribed and illustrated are merely convenient and useful forms of theinvention which is capable of many other modifications without departingfrom the spirit and scope of the invention as defined by the appendedclaims. What is claimed is: 1. In a device for determining the conditionof a gas, an indicating means, a chamber means for introducing the gasto be teste into the chamber, a sheet of metal having a surface coatedwith latinum black, a source tering a beam of light therefrom, means fordirecting said beam of light on the platinum black surface, a lightsensitive means positioned within the chamber, means for protecting thelight sensitive means from any direct light from the source thereof,means for refrigerating the sheet of metal to effect the precipitationof a condensation from the gas upon the platinum black surface toreflect a beam of light into the light sensitive means, and means resonsive to the energiaation of the light sensitive means for operatingthe indicating mea air in the Dewar .2. In a device for determining thecondi- I tion ofja gas, an indicating means, a chamber, e gas to betested into the chamber, a metallic non-light reflecting element withinsaid chamber, 'a light sensitive means itioned withinsaid'c amber, meansfor a tering the temperature of said metallic non light reflectingelement to effect the precipitation of a condensation-from the gas uponsaid element to reflect a beam of means responsive topthe energizationofthe light sensitive means by said reflected beam of light for 0 eratingsaid indicating means and means or indicating the temperature of saidelement.

In witness whereof, I hereunto subscribe my name this 31st day ofJanuary A. D., 1929.

' MALCOLI CLAIR! WIYANT TOILINSON.

